Typically, in an excavator, an operator operates an operating lever, so that a work machine including a bucket is driven. At this time, when excavating a slope having a predetermined inclination or a groove having a predetermined depth, it is difficult for the operator to judge whether accurately excavating the slope or the groove according to a targeted shape only by visually recognizing the movement of the work machine. Also, the operator is required to have a high degree of skill to efficiently and accurately excavate the slope having a predetermined inclination, according to the targeted shape. Therefore, for example, there is a technology of displaying position information of the bucket positioned at a tip of the work machine in a display device and supporting the operator (for example, Patent Literature 1).